Different types of electronic devices have a dominant position in our daily life. Modern devices are capable of executing complex tasks and they have various functionalities. For example, in mobile phones there are many features that do not relate to the original purpose of a phone. Cameras, GPS-navigators and music players are standard features in mobile phones and more features are to be expected in the near future. Because of the vast set of features, mobile phones and other electronic devices are harder to use than in the early days. Most of the users do not have the energy needed for studying how all of the features work, so many users cannot use all of the features that the devices are capable of executing.
This problem has been recognized. Thus, usability engineers and user interface designers seek continuously new solutions for providing easier and more convenient way of using such devices. Menu structures and input devices are under continuous construction in order to provide better user experience. One good example is the recently developed touch screen technology that can be used with fingers. It is a more flexible and natural way than a keypad and easier to use than a touch screen that requires a pen for input. Even if these solutions already provide better user interfaces, there is still need for even better and different ways for using different applications. Thus, there is a continuous need for improved user interfaces.